(1) Field of the Invention
The present invention pertains to a fire stop outlet for a small duct, high velocity air distribution system. In particular, the present invention pertains to a fire stopping apparatus that is assembled to a duct opening and is communicated with a high velocity air duct. The fire stopping apparatus comprises a cylindrical metal wall supporting a cylindrical band of intumescent material that expands and closes the air duct opening when subjected to the heat of a fire.
(2) Description of the Related Art
Fire damper assemblies are often used at the air outlets or air inlets of heating and cooling air distribution systems for buildings. The typical fire damper assembly includes one or more dampers positioned in an air distribution system opening. The dampers are held in an open position to allow the free flow of air through the opening. However, when the damper assembly is subjected to intense heat resulting from a fire in the building, the heat triggers a release mechanism of the damper assembly and the dampers automatically move to closed positions in the air distribution system opening. This prevents fire on one side of a wall or a ceiling panel from passing through the air distribution opening to the opposite side of the wall or ceiling panel.
Use of the prior art fire damper assemblies is not practical in air distribution systems that are small duct, high velocity systems. In small duct, high velocity air distribution systems, the duct openings are much smaller, with a duct opening usually having less than six square inches of open area. The prior art fire damper assemblies are too large to be used in such a small opening, and it is impractical to design a fire damper assembly that is sufficiently reduced in size to be used in the smaller, typically circular opening of a small duct, high velocity air distribution system.